UVA 10127 solution

UVA 10127 solution

#include<stdio.h>

int long long bigmod(int long long  a ,int p,int m);
int main()
{
      int long long a;
      int long long p,m,n,t;
            int c;

            while(scanf("%lld",&n)==1){
            c=1;
            t=10;
            a=1;
                              while(a%n!=0){
                                    a=a*t+1;
                                     c++;
                                     a=bigmod(a,1,n);
                              }
                              printf("%d\n",c);
            }



      return 0;
}

int long long  bigmod(int long long  a ,int p,int m)
{
            if(p==0)
            return 1;

            if(p%2==0){                  // p is even then split it up and mod
            int c=bigmod(a,p/2,m);
            return ( (c%m) * (c%m) )%m;
            }
            else  // p is odd then make it even
            return ( (a%m)* bigmod(a,p-1,m) ) %m;

}