#include <stack>
#include <vector>
#include <string>
#include <fstream>
#include <algorithm>
#define pb push_back

/*
 *
 */
using namespace std;
typedef string::iterator iter;
ifstream in;
ofstream out;
int constant[30];
string Functions[30];
inline int priority( char x )
{
	if( '(' == x )
		return 0;
	if( '+' == x || '-' == x )
		return 1;
	if( '*' == x || '/' == x )
		return 2;
	if( ')' == x )
		return 3;
	return -1;
}
string transform( iter it, iter iend )
{int p;
 stack<char> s;
 string t;
	while( it < iend )
	{
		if( *it >= 'a' && *it <= 'b' )
		{
			t.pb(*it); ++it;
			continue;
		}
		if( *it >= '0' && *it <= '9' )
		{
			while( it < iend && *it >= '0' && *it <= '9' )
				t.pb(*it), ++it;
			t.pb(' ');
			continue;
		}
		if( '(' == *it )
		{
			s.push(*it); ++it;
			continue;
		}
		if( ')' == *it )
		{++it;
			while( !s.empty() && '(' != s.top() )
				t.pb(s.top()), s.pop();
			s.pop();
			continue;
		}
		p=priority(*it);
		while( !s.empty() && p <= priority(s.top()) )
			t.pb(s.top()),s.pop();
		s.push(*it); ++it;
	}
	while( !s.empty() )
		t.pb(s.top()),s.pop();
	return t;
}
inline int getnumber( iter& it, iter iend )
{int number=0;
	while( it < iend && *it >= '0' && *it <= '9' )
		number=number*10+*it-'0', ++it;
	return number;
}
int evaluate( iter it, iter iend, vector<int>* arguments )
{int number, a, b;
 stack<int> v;
	while( it < iend )
	{
		if( *it >= 'a' && *it <= 'z' )
		{
			v.push( arguments->at(*it-'a') ); ++it;
			continue;
		}
		if( *it >= '0' && *it <= '9' )
		{
			v.push( getnumber( it, iend ) );
			++it;
			continue;
		}
		b=v.top(); v.pop();
		a=v.top(); v.pop();
		switch(*it)
		{
			case '+' : v.push(a+b); break;
			case '-' : v.push(a-b); break;
			case '*' : v.push(a*b); break;
			case '/' : v.push(a/b); break;
		}
		++it;
	}
	return v.top();
}
int main()
{string expresion;
	in.open("evaluare.in");
	getline( in, expresion );
	expresion=transform( expresion.begin(), expresion.end() );
	out.open("evaluare.out");
	out<<evaluate( expresion.begin(), expresion.end(), NULL );
	return 0;
}