#include<iostream> using namespace; struct two { int a; int b; }t[100]; int main() { int n; cin>>n; for(int i=0;i<n;i++) { cin>>t[i].a>>t[i].b; } int l=1000; int fish=0,sum=0; for(int i=0;i<n;i++) { if(t[i].a<=l||fish==0) { sum+=t[i].a; l=t[i].a+t[i].b; fish++; continue; } if(l<t[i].a) { sum+=l; l+=t[i].b; fish++; } } cout<<sum; return 0; }