Hello, this is my code:

#include <iostream>
#include <string.h>
using namespace std;
int main()
{	ios_base::sync_with_stdio(false);
	string s,t,n;
    int s1=0,t1=0,n1=0;
	cin>>s;
	cin>>t;
	for(int i=0;i<s.length();i++)
    {
        n[i]=((int)s[i]+(int)t[i])/2;
    }
    for(int i=0;i<s.length();i++)
    {
        s1+=(int)s[i];
        t1+=(int)t[i];
        n1+=(int)n[i];
    }
   if((n1>s1)&&(n1<t1))
    {
        for(int y=0;y<s.length();y++)
        cout<<n[y];
    }
    else
        cout<<"No such string";
return 0;
}

This code runs successfully on Codeblocks & Codechef IDE but when I submit this on Codeforces (GNU G++11 4.9.2) I get runtime error on sample test 3 (abcdefg,abcdefh)

Please suggest me how to fix this error.