var t1,t2,m,c: real;begin write('t1='); readln(t1); write('t2='); readln(t2); write('m='); readln(m); write('c='); readln(c); writeln('Q=', c*m*(t2-t1));end.
var
t1,t2,m,c: real;
begin
write('t1='); readln(t1);
write('t2='); readln(t2);
write('m='); readln(m);
write('c='); readln(c);
writeln('Q=', c*m*(t2-t1));
end.