C++ :

#include<iostream>
using namespace std;
int a[100];
int main()
{
	int m;
	cin>>m;
	a[1]=1;
	a[2]=1;
	for(int i=3;i<=m;++i)
	a[i]=a[i-1]+a[i-2];
	cout<<a[m];
	return 0; 
}

Pascal :

var
   n,a,b,i,c:longint;
begin
 readln(n);
 a:=1;
 b:=1;
 for i:=3 to n do
  begin
   c:=b;
   b:=a+b;
   a:=c;
  end;
 writeln(b);
end.