/*
TASK: minjumps
LANG: C++
*/
#include<iostream>
#include<vector>
using namespace std;
vector <int > v;
int main()
{
    int a,b,n,c,d,i,br=0,p=0;
    cin>>a>>b>>n;
    if(b>a)swap(a,b);
    if(a%2==0&&b%2==0&&n%2==1){cout<<-1<<'\n';p=1;}
    if(n%a==0&&!p){cout<<n/a<<'\n';p=1;}
    if(a%b==0||b%a==0)
    {
                      if(b!=1&&!p)
                      if(n%a!=0){p=1;cout<<-1<<'\n';}}
    if(n>=0&&!p){
    for(i=0;i<10000;i+=a)
    {
                         if(i>n&&(i-n)%b==0){c=br+(i-n)/b;break;}
                         else
                         if(i<n&&(n-i)%b==0)d=br+(n-i)/b;
                         br++;
    }
    if(c!=0&&c<d)cout<<c<<'\n';
    if(d<c)cout<<d<<'\n';
    if(n!=0&&d==0&&c==0)cout<<-1<<'\n';
}
    if(n<0&&!p)
    {
    for(i=0;i>-10000;i-=a)
    {
                         if(i>n&&((n*-1)+i)%b==0)c=br+((n*-1)+i)/b;
                         else
                         if(i<n&&((i*-1)+n)%b==0){d=br+((i*-1)+n)/b;break;}
                         br++;
    }
    if(d!=0&&d<c)cout<<d<<'\n';
    if(c<d)cout<<c<<'\n';
    if(d==0&&c==0)cout<<-1<<'\n';
}
return 0;
}

                    
