Ignatius and the Princess III

Problem Description
“Well, it seems the first problem is too easy. I will let you know how foolish you are later.” feng5166 says.

“The second problem is, given an positive integer N, we define an equation like this:
N=a[1]+a[2]+a[3]+…+a[m];
a[i]>0,1<=m<=N;
My question is how many different equations you can find for a given N.

Input
The input contains several test cases. Each test case contains a positive integer N(1<=N<=120) which is mentioned above. The input is terminated by the end of file.

Output
For each test case, you have to output a line contains an integer P which indicate the different equations you have found.

Sample Input
4
10
20

Sample Output
5
42
627

#include<bits/stdc++.h>
using namespace std;
int i,j,dp[121]={0},n,s[121];
void fun()
{
    for(i=0;i<121;i++)
    {
        s[
 
i]=i;
    }
    dp[0]=1;
    for(i=1;i<121;i++)
    {
        for(j=s[i];j<121;j++)
        {
            dp[j]=dp[j-s[i]]+dp[j];
        }
    }
}
int main()
{
    fun();
    while(cin>>n)
    {
        printf("%d\n",dp[n]);
    }
}