Grass Seed Inc.

#include <iostream>

using namespace std;

typedef long double ld;

int main() {
	ld c;
	int l;
	cin >> c >> l;
	ld r = 0;
	for (int i = 0; i < l; i++) {
		ld w, h;
		cin >> w >> h;
		r += w*h;
	}
	r *= c;
	cout.precision(20);
	cout << fixed << r << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED