#include <bits/stdc++.h>
#define all(v) (v).begin(),(v).end()
using namespace std;
void solve(long long D, long long G, std::vector<long long> p, std::vector<long long> c){
vector<int> v(D);
iota(all(v), 0);
int ans = 1e9;
while (true) {
int solve = 0, score = 0;
for (auto i: v) {
int plus_score = 100*(i+1)*p[i] + c[i];
if (score + plus_score <= G) {
solve += p[i];
score += plus_score;
} else {
int less = G - score;
long long part_score = 100 * (i + 1);
if (less > 0) solve += min(p[i], (less+(part_score-1))/part_score);
break;
}
}
ans = min(ans, solve);
if (!next_permutation(all(v))) break;
}
cout << ans << endl;
}
// Generated by 1.1.6 https://github.com/kyuridenamida/atcoder-tools (tips: You use the default template now. You can remove this line by using your custom template)
int main(){
long long D;
scanf("%lld",&D);
long long G;
scanf("%lld",&G);
std::vector<long long> p(D);
std::vector<long long> c(D);
for(int i = 0 ; i < D ; i++){
scanf("%lld",&p[i]);
scanf("%lld",&c[i]);
}
solve(D, G, std::move(p), std::move(c));
return 0;
}