Have a look at the examples in Serial Input Basics - simple reliable ways to receive data.
The technique in the 3rd example will be the most reliable.
You can send data in a compatible format with code like this
Serial.print('<'); // start marker
Serial.print(value1);
Serial.print(','); // comma separator
Serial.print(value2);
Serial.println('>'); // end marker
And if you need more help please post your complete program.
...R