/* The Great Computer Language Shootout
   http://shootout.alioth.debian.org/

   contributed by Jeffrey Stedfast
*/

using System;
using System.IO;

class SumCol2 {
	static int SumStream (Stream stream)
	{
		byte[] buf = new byte [4097];
		int nread, n, v = 0;
		bool negate = false;
		bool first = true;
		int sum = 0;
		char c;
		
		do {
			if ((nread = stream.Read (buf, 0, 4096)) <= 0)
				break;
			
			buf[nread] = (byte) '\n';
			n = 0;
			
			do {
				if (first) {
					if (buf[n] == (byte) '-') {
						negate = true;
						first = false;
						n++;
					} else if (buf[n] != (byte) '\n')
						first = false;
				}
				
				while (buf[n] != (byte) '\n') {
					c = (char) buf[n];
					if (c < '0' || c > '9') {
						Console.WriteLine ("{0} not a digit, v is {1}", c, v);
						throw new Exception ();
					}
					
					v = v * 10 + (c - '0');
					n++;
				}
				
				if (n == nread)
					break;
				
				if (negate)
					sum -= v;
				else
					sum += v;
				
				negate = false;
				first = true;
				v = 0;
				
				n++;
			} while (true);
		} while (true);
		
		if (negate)
			sum -= v;
		else
			sum += v;
		
		return sum;
	}
	
	static void Main ()
	{
		Stream stdin = Console.OpenStandardInput ();
		int sum;
		
		try {
			sum = SumStream (stdin);
			Console.WriteLine (sum);
		} catch {
			Console.WriteLine ("Invalid input");
		}
	}
}