문제출처 : https://www.acmicpc.net/problem/2869
code
#include <iostream>
#include <cmath>
using namespace std;
int main()
{
double A, B, V, m;
int day = 1;
cin >> A >> B >> V;
m = A - B;
day += ceil((V - A) / m);
cout << day;
return 0;
}