cf Perfect Pair

http://codeforces.com/contest/318/problem/C

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 using namespace std;
 long long j;
 long long x,y,m;
 int main()
 {
     scanf("%I64d%I64d%I64d",&x,&y,&m);
     if(x>=m||y>=m)
     {
         printf("0\n");
         return ;
     }
     else if(x<=&&y<=)
     {
         printf("-1\n");
         return ;
     }
     if(x<)
     {
         j=(-x)/y+;
         x+=j*y;
     }
     if(y<)
     {
         j=(-y)/x+;
         y+=j*x;
     }
     while()
     {
         if(!(x<m&&y<m)) break;
         if(x>y) y=x+y;
         else x=x+y;
         j++;
     }
     printf("%I64d\n",j);
     return ;
 }