import std;

int calc(long x) {
    long s = 100;
    int k = 0;
    while (s < x) {
        s += s / 100;
        k++;
    }
    return k;
}

void main() {
    long x; scan(x);
    writeln(calc(x));
}

void scan(T...)(ref T a) {
    string[] ss = readln.split;
    foreach (i, t; T) a[i] = ss[i].to!t;
}
T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;
