#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct Coin{ int value, amount; bool operator < (const Coin &t)const{ return value < t.value; }}coin[22];int need[22];int main() { ios_base::sync_with_stdio(0); int n, c; cin >> n >> c; for (int i = 0; i < n; ++i) cin >> coin[i].value >> coin[i].amount; sort(coin, coin + n); int ans = 0; while (1){ int rest = c; memset(need, 0, sizeof need); for (int i = n - 1; i >= 0; --i){ if (coin[i].amount > 0){ int require = min(coin[i].amount, rest / coin[i].value); rest -= require * coin[i].value; need[i] = require; } if (rest == 0) break; } if (rest > 0){ for (int i = 0; i < n; ++i){ if (coin[i].amount > 0 && coin[i].value >= rest){ rest = 0; ++need[i]; break; } } } if (rest > 0) break; int week = 0x3f3f3f3f; for (int i = 0; i < n; ++i) if (need[i]) week = min(week, coin[i].amount / need[i]); for (int i = 0; i < n; ++i) if (need[i]) coin[i].amount -= week * need[i]; ans += week; } cout << ans << 'n'; return 0;}
