function MinInt(a,b:Integer):Integer;
begin
if a < b then MinInt := a else MinInt := b;
end;
var x,y,z,t:Integer;
begin
writeln('x='); readln(x);
writeln('y='); readln(y);
writeln('z='); readln(z);
writeln('t='); readln(t);
writeln('min=', MinInt(MinInt(x, y), MinInt(z, t)));
end.