// Mugurel Ionut Andreica
// Convert all the probabilities into integers with up to 4 digits and multiply them into a big number using a large base which is a power of 2 (in order to have quick division and modulo operations).

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define DEBUG 0
#define NMAX 8010
#define BASE 262144
#define BASEMOD 262143
#define BASEBITS 18

typedef unsigned int BigNum[NMAX];

inline void Multiply(BigNum v, unsigned int x) {
	unsigned int i;
	if (x == 0) {
		memset(v, 0, (v[0] + 1) * sizeof(int));
		v[0] = 1;
		return;
	}
	if (x == 1) return;
	v[1] *= x;
	for (i = 1; i <= v[0]; i++) {
		v[i + 1] *= x;
		if (v[i] >= BASE) {
			v[i + 1] += (v[i] >> BASEBITS);
			v[i] &= BASEMOD;
		}
	}
	for (i = v[0] + 1; v[i] > 0; i++) {
		if (v[i] >= BASE) {
			v[i + 1] += (v[i] >> BASEBITS);
			v[i] &= BASEMOD;
		}
	}
	v[0] = i - 1;
}

void Add(BigNum A, BigNum B) {
	unsigned int i, ndigits = A[0];
	if (B[0] > ndigits) ndigits = B[0];
	for (i = 1; i <= ndigits; i++) A[i] += B[i];
	A[0] = ndigits;
	for (i = 1; i <= A[0]; i++)
		if (A[i] >= BASE) {
			A[i + 1] += (A[i] >> BASEBITS);
			A[i] &= BASEMOD;
			if (i == A[0]) A[0]++;
		}
}

void Subtract(BigNum A, BigNum B) {
	unsigned int i, j;
	for (i = 1; i <= A[0]; i++) {
		if (A[i] < B[i]) {
			j = i + 1;
			while (j <= A[0] && A[j] == 0) j++;
			A[j]--;
			j--;
			while (j > i) {
				A[j] = BASE - 1;
				j--;
			}
			A[i] += BASE;
		}
		A[i] -= B[i];
	}
	while (A[0] > 1 && A[A[0]] == 0) A[0]--;
}

int Equal(BigNum A, BigNum B) {
	if (A[0] != B[0]) return 0;
	for (unsigned int i = 1; i <= A[0]; i++)
		if (A[i] != B[i]) return 0;
	return 1;
}

int LessThanOrEqual(BigNum A, BigNum B) {
	if (A[0] < B[0]) return 1;
	if (A[0] > B[0]) return 0;
	for (int i = A[0]; i >= 1; i--) {
		if (A[i] < B[i]) return 1;
		if (A[i] > B[i]) return 0;
	}
	return 1;
}

void PrintBigNum(BigNum A) {
	int i;
	fprintf(stderr, "%d", A[A[0]]);
	for (i = A[0] - 1; i >= 1; i--)
		fprintf(stderr, "%04d", A[i]);
	fprintf(stderr, "\n");
}

char frac[10];
BigNum A, B, SUM;
int N, M;

int main() {
	int T, i, j, k, x, y;
	scanf("%d", &T);
	while (T--) {
		scanf("%d %d", &N, &M);
		memset(SUM, 0, sizeof(SUM));
		SUM[0] = 1;
		for (i = 0; i < N; i++) {
			memset(B, 0, sizeof(B));
			B[0] = B[1] = 1;
			for (j = 0; j < M; j++) {
				scanf("%d.%s", &x, frac);
				if (x == 0) {
					y = 0;
					sscanf(frac, "%d", &y);
					for (k = strlen(frac); k < 4; k++)
						y *= 10;
					x = x * 10000 + y;
				} else x = 10000;
				Multiply(B, x);
			}
			if (i == 0) memcpy(A, B, sizeof(BigNum));
			Add(SUM, B);
			if (DEBUG) {
				fprintf(stderr, "i=%d: %d", i, B[0]);
				//PrintBigNum(B);
				fprintf(stderr, "\n");
			}
		}
		if (DEBUG) {
			fprintf(stderr, "SUM= %d", SUM[0]);
			//PrintBigNum(SUM);
			fprintf(stderr, "\n");
		}
		if (A[0] == 1 && A[1] == 0) printf("0.000000000\n");
		else if (Equal(A, SUM)) printf("1.000000000\n");
		else {
			printf("0.");
			// Find all the digits, one by one.
			for (int digit = 1; digit <= 9; digit++) {
				Multiply(A, 10);
				int li = 0, ls = 9, mid, ans = 0;
				while (li <= ls) {
					mid = (li + ls) >> 1;
					memcpy(B, SUM, sizeof(BigNum));
					Multiply(B, mid);
					if (LessThanOrEqual(B, A)) {
						ans = mid;
						li = mid + 1;
					} else {
						ls = mid - 1;
					}
				}
				printf("%d", ans);
				if (ans > 0) {
					memcpy(B, SUM, sizeof(BigNum));
					Multiply(B, ans);
					Subtract(A, B);
				}
			}
			printf("\n");
		}
	}
	return 0;
}