C :

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int a,b,c,d,min1,min2;
    scanf("%d%d%d%d",&a,&b,&c,&d);
    if(a<=b)
        min1=a;
    else
        min1=b;
    if(c<=d)
        min2=c;
    else
        min2=d;
    if(min1<=min2)
        printf("%d",min1);
    else
        printf("%d",min2);

}

C++ :

#include<iostream>
using namespace std;
int main()
{
	int a,b,c,d;
	cin>>a>>b>>c>>d;
	int max=a;
	if (max>b) max=b;
	if (max>c) max=c;
	if (max>d) max=d;
	cout<<max<<endl;
	return 0;
}

Pascal :

program  p2651(input,output);
var
  a,b,c,d,e:longint;
begin
  readln(a,b,c,d);
  if (a>b) then e:=b else e:=a;
  if (e>c) then e:=c;
  if (e>d) then e:=d;
  writeln(e);
end.