Do better error handling on inputs

calc.py

-operand1 = int(input("First operand: "))
+operand1 = input("First operand: ")
 operator = input("Operator: ")
-operand2 = int(input("Second operand: "))
+operand2 = input("Second operand: ")
+
+try:
+    operand1 = int(operand1)
+except ValueError:
+    print(operand1 + " is not a number!")
+    exit(1)
+
+try:
+    operand2 = int(operand1)
+except ValueError:
+    print(operand1 + " is not a number!")
+    exit(1)
 
 print("Your result is:")
 if operator == "+":