1031 Hello World for U

#include<iostream>
#include<string>
using namespace std;
int main(){
    string s;
    cin>>s;
    int len = s.length()+2;
    int n1 = len/3,n2 = len/3+len%3;
    string s1 = s.substr(0,n1-1),s2 = s.substr(n1-1,n2),s3 = s.substr(n1+n2-1,n1-1);
    for(int i = 0,j = n1-2;i<n1-1,j>=0;i++,j--){
        cout<<s1[i];
        for(int x = 0;x<n2-2;x++)
            cout<<" ";
        cout<<s3[j]<<endl;
    }
    cout<<s2<<endl;
    return 0;
}