#include <bits/stdc++.h> using namespace std; int n; int x, y; int cnt, ans;

int main() { cin >> n; while (n--) { cin >> x >> y; ans = x * 7 / 10; for (int i = 1; i <= y; i++) { x = x * 95 / 100; } cnt += max(x, ans); } cout << cnt; return 0; }