#include<iostream>
#include<cstdio>
using namespace std;
string a,b,c;
long long d,i,j,p,q,n,m,k;
int sravni(string s,string f)
{
    int ds,df,i;
    ds=s.size()-1;
    df=f.size()-1;
    if(ds>df)return 1;
    if(df>ds)return 0;
    for(i=0;i<=ds;i++)
    {
        if(s[i]>f[i])return 1;
        if(f[i]>s[i])return 0;
    }
    return -1;
}
void izravni(string &s,string &f)
{
    int ds,df;
    int i;
    ds=s.size()-1;
    df=f.size()-1;
    while(ds<df){s='0'+s;ds++;}
    while(df<ds){f='0'+f;df++;}
}
string saberi(string s,string f)
{
    int ds,df,i,k,j=0;
    string a="";
    izravni(s,f);
    //cout<<s<<" "<<f<<endl;
    ds=s.size()-1;
    df=f.size()-1;
    for(i=ds;i>=0;i--)
    {
        k=(s[i]-'0')+(f[i]-'0')+j;
        j=k/10;
        k%=10;
        a=char(k+'0')+a;
    }
    if(j>0)a=char(j+'0')+a;
    return a;
}
string umnoji1(string s,int f)
{
    int ds,k,t=0,i;
    string a="";
    ds=s.size()-1;
    for(i=ds;i>=0;i--)
    {
        k=(s[i]-'0')*f+t;
        t=k/10;
        k%=10;
        a=char(k+'0')+a;
    }
    if(t>0)a=char(t+'0')+a;
    return a;
}
string umnoji2(string s,string f)
{
    int ds,df,br=0,i,j;
    string a="",b="";
    if(sravni(s,f)==0)swap(s,f);
    df=f.size()-1;
    for(i=df;i>=0;i--)
    {
        b=umnoji1(s,f[i]-'0');
        for(j=1;j<=br;j++)
        {
            b=b+'0';
        }
        br++;
        a=saberi(a,b);
    }
    return a;
}
string izvadi(string s,string f)
{
    int ds,df,i,k=0,t;
    string a="";
    if(sravni(s,f)==0)swap(s,f);
    izravni(s,f);
    //cout<<s<<" "<<f<<endl;
    ds=s.size()-1;
    df=f.size()-1;
    for(i=ds;i>=0;i--)
    {
        if((s[i]-'0')-(f[i]-'0')+k<0)
        {
            t=(s[i]-'0')-(f[i]-'0')+k+10;
            k=-1;
        }
        else
        {
            t=(s[i]-'0')-(f[i]-'0')+k;
            k=0;
        }
        a=char(t+'0')+a;
    }
    while(a[0]=='0')a.erase(0,1);
    return a;
}
string razdeli(string s,long long f)
{
    long long ds,df,i,p=0;
    string a="";
    ds=s.size()-1;
    //cout<<s<<" "<<f<<endl;
    bool fl=0;
    for(i=0;i<=ds;i++)
    {
        p=p*10+(s[i]-'0');
        //cout<<p<<endl;
        if(p==0)a=a+'0';
        else if(p>=f){a=a+char(p/f+'0');p%=f;fl=1;}
        else if(fl==1 && p<f)a=a+'0';
    }
    if(p>0)a=a+char(p/f+'0');
    return a;
}
int main()
{
    freopen("symbiosis.in", "r", stdin);
    freopen("symbiosis.out", "w", stdout);
    cin>>a>>b>>c;
    string help = umnoji2(a,c),kkk="1",ppp;
    long long br=0;
    while(sravni(b,help)!=0)
    {
       // cout<<a<<endl;
        b=izvadi(b,help);
        br++;
        if((a[a.size()-1]-'0')%2==1)ppp=izvadi(a,kkk);
        else ppp = a;
        a = saberi(a,razdeli(ppp,2));
        help = umnoji2(a,c);
    }
    cout<<br;
    return 0;
}