C++ :

#include<bits/stdc++.h>
using namespace std;
long long n,L=1,R,M;
long long check(long long x)
{
	return trunc(log(x)/log(10)*x)+1;
}
int main()
{
    cin>>n;R=n;
	while(L<=R)
	{
		M=(L+R)/2;
		if(check(M)>=n)R=M-1;
		else L=M+1;
	}    
	cout<<L;
    return 0;
}

Pascal :

program p1003;
var m,n,l,r:longint;
Function check:boolean;
Begin
  m:=(l+r) shr 1;
  if (m*ln(m)/ln(10))>=n-1 then exit(true) else exit(false);
End;
begin
Readln(n);
L:=1; r:=200000000;
While l<>r do
If check then r:=m else l:=m+1;
Writeln(l);
End.