Folding

As you can remember, Alex is fond of origami. She switched from squares to rectangles, and rectangles are much more difficult to master. Her main interest is to determine what is the minimum possible number of folds required to transform W× H rectangle to w × h one. The result of each fold should also be rectangular, so it is only allowed to make folds that are parallel to the sides of the rectangle.

Help Alex and write a program that determines the minimum required number of folds.

#include <bits/stdc++.h>
using namespace std;

int solve(double a,double b, double x,double y)
{
    int ans = 0;
    while( x*2 < a )
    {
        ans++;
        a/=2;
    }
    while( y*2 < b )
    {
        ans++;
        b/=2;
    }
    if( x < a )ans++;
    if( y < b )ans++;
    return ans;
}

int main()
{
    double a,b;
    double x,y;
    while( cin >> a >> b >> x >> y )
    {
        if( a < b )swap(a,b);
        if( x < y )swap(x,y);
        if( a < x || b < y ){
            printf("-1\n");
            continue;
        }
        int ans = solve(a,b,x,y);
        ans = min( ans , solve(b,a,x,y) );
        printf("%d\n",ans);
    }
}