#include<bits/stdc++.h>
using namespace std;
int main(){

	double a,b,c=10000000,s,x=2;
    cin>>a>>b>>s;
    if(a>s) cout<<1;
    else if(b>s) cout<<2;
    else{
        while(1){
        x++;
        c=sqrt(pow(a,2)+pow(b,2));
        if(c>s){
            cout<<x;
            return 0;
        }
        a=b;
        b=c;
        } 
    }
   
    
	return 0;
}