# include <stdio.h>

int main(void) {
	int N, T;
	scanf("%d%d", &N, &T);

	int a[200] = {0};
	int b[200] = {0};

	int i, j;
	for (i = 0; i < N; ++i) {
		scanf("%d%d", &a[i], &b[i]);
	}
	float c[100] = {0};
	for (i = 0; i < N; ++i) {
		c[i] = b[i] / (float)(a[i]);
	}
	int t, t1, t2;
	for (i = 0; i < N; ++i) {
		for (j = 0; j < N - i - 1; ++j) {
			if (c[j] < c[j + 1]) {
				t2 = c[j];
				t = a[j];
				t1 = b[j];
				a[j] = a[j + 1];
				b[j] = b[j + 1];
				c[j] = c[j + 1];
				a[j + 1] = t;
				b[j + 1] = t1;
				c[j + 1] = t2;
			}
		}
	}

	int num = 0;
	int num2 = 0;
	for (i = 0; i < N; ++i) {
		num += a[i];
		num2 += b[i];
		if (num > T) {
			break;
		}
	}
	num -= a[i];
	num2 -= b[i];
	float num1 = 0;
	num1 = b[i] / (float)(a[i]);
	printf("%.2f", (float)(num2) + num1 * (T - num));


	return 0;
}