#include<stdio.h>
int sum(int n)
{
int i,s=0;
for(i=1;i<=n;i++) s=s+i;
return s;
}void main()
{
int (*print)()=&printf;
int (*scan)()=&scanf;
int(*f)()=sum;
int n; (*scan)("%d",&n);
(*print)("1+2+3+...+100=%d\n",f(n));
}