请在代码前面加上\`\`\`cpp
结尾加上\`\`\`
by floatery @ 2019-03-28 18:25:16
希望更丰富的展现？使用Markdown
```cpp
#include<bits/stdc++.h>
using namespace std;
int main() {
int n,m,a,b,sum=0,s=0;
map<int,int> vc;
map<int,int>::iterator iter;
cin>>n>>m;
for(int i=0;i<m;i++) {
cin>>a>>b;
vc[a]=b;
}
for(iter=vc.begin();iter!=vc.end();iter++) {
if(iter->second+sum>=n) {
s+=(n-sum)iter->first;
break;
} else {
s+=iter->firstiter->second;
sum+=iter->second;
}
}
vc.clear();
cout<<s<<endl;
return 0;
}
```
by DepletedPrism @ 2019-03-28 18:36:14