1 способ
program a1;
var
a,b,c, min:real;
begin
readln(a,b,c);
if ( a < b ) and ( a < c ) then min:=a;
if ( b < a ) and ( b < c ) then min:=b;
if ( c < b ) and ( c < a ) then min:=c;
writeln('min=', min);
end.
2 способ
program a2;
var
a,b,c, min, min1:real;
begin
readln(a,b,c);
if a < b then min1:=a else min1:=b;
if min1 < c then min:=min1 else min:=c;
writeln('min=', min);
end.
3 способ
program a3;
var
a,b,c, min:real;
begin
readln(a,b,c);
if ( a < b ) and ( a < c ) then min:=a
else
if ( b < a ) and ( b < c ) then min:=b
else min:=c;
writeln('min=', min);
end.