The algorithm in Figure 1 is designed to check if a chemical reaction's target temperature is valid (at least 80 degrees Celsius) and calculate the required temperature rise from a starting temperature. It contains a logic error on line 11.

Figure 1

1  validRun ← False
2  REPEAT
3      tempRise ← 0
4      OUTPUT 'Enter starting temperature: '
5      startingTemp ← USERINPUT
6      OUTPUT 'Enter target temperature: '
7      targetTemp ← USERINPUT
8      IF startingTemp ≥ targetTemp THEN
9          OUTPUT 'Starting temperature must be less than target temperature'
10     ELSE
11         IF targetTemp ≥ 80 THEN
12             OUTPUT 'Target temperature must be at least 80 degrees'
13         ELSE
14             validRun ← True
15         ENDIF
16     ENDIF
17 UNTIL validRun = True
18 tempRise ← targetTemp - startingTemp
19 OUTPUT tempRise