求助：HDU 3880 luck number的规律是怎么找出来的?

求助：HDU 3880 luck number的规律是怎么找出来的?
求助：HDU 3880 luck number的规律是怎么找出来的?

求助：HDU 3880 luck number的规律是怎么找出来的?
//
#include
#include
#include
int main(){
__int64 i,j,k;
__int64 a,b,M;
while(scanf("%I64d%I64d%I64d",&a,&b,&M) != EOF){
if (a > b){
k = a;
a = b;
b = k;
}
if (b == 1){
k = M;
}else{
k = 0;
j = 1;
for (i = b; M / i > 0; i = i * b){
k += j * M / i;
j = -j;
}
}
printf("%I64d\n",k);
}
//system("pause");
return 0;
}