UVA 10219 - Find the ways !

//...................SUBHASHIS MOLLICK...................///
///.....DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING....///
///.............ISLAMIC UNIVERSITY,BANGLADESH.............///
///....................SESSION-(14-15)....................///
#include<bits/stdc++.h>
using namespace std;
#define sf(a) scanf("%lld",&a)
#define sf2(a,b) scanf("%lld %lld",&a,&b)
#define sf3(a,b,c) scanf("%lld %lld %lld",&a,&b,&c)
#define pf(a) printf("%lld",a)
#define pf2(a,b) printf("%lld %lld",a,b)
#define pf3(a,b,c) printf("%lld %lld %lld",a,b,c)
#define nl printf("\n")
#define ll long long
#define pb push_back
#define MPI map<int,int>mp;
#define fr(i,n) for(i=0;i<n;i++)
#define fr1(i,n) for(i=1;i<=n;i++)
#define frl(i,a,b) for(i=a;i<=b;i++)
//freopen("Input.txt","r",stdin);
//freopen("Output.txt","w",stdout);
//const int fx[]={+1,-1,+0,+0};
//const int fy[]={+0,+0,+1,-1};
//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move
//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move
//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move
//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move
main()
{
    long long n,m;
    while(cin>>n>>m)
    {
        long i,ans;
        double sum=0.0,sum1=0.0;
        for(i=(n-m+1);i<=n;i++)
        {
            sum+=(log10(double(i)));
        }
        for(i=1;i<=m;i++)
        {
            sum1+=(log10(double(i)));
        }
        sum-=sum1;
        ans=sum;
        cout<<ans+1<<endl;
    }
}