codeforces 116A - Tram

#include<stdio.h>
int main()
{
int a,b,i,max=0,n,x=0;
scanf("%d",&n);
for(i=0;i<n;i++)
{
scanf("%d%d",&a,&b);
x-=a;
x+=b;
if(x>max) max=x;
}
printf("%dn",max);
return 0;
}