var
s:string;
n,t,i,k:longint;
a:array[1..100] of longint;
begin
readln(s);
n:=length(s);
i:=1; t:=0;
while i<=n do
begin
case s[i] of
'0'..'9':
begin
k:=0;
while s[i]<>'.' do
begin
k:=10*k+ord(s[i])-48;
inc(i);
end;
t:=t+1; a[t]:=k;
end;
'+':begin a[t-1]:=a[t-1]+a[t]; dec(t);end;
'-':begin a[t-1]:=a[t-1]-a[t]; dec(t);end;
'*':begin a[t-1]:=a[t-1]*a[t]; dec(t);end;
'/':begin a[t-1]:=a[t-1] div a[t]; dec(t);end;
end;{case}
i:=i+1;
end;{while}
Writeln(a[1]);
End.

分析一下程序