input_lines = None

with open("input.txt","r") as f:
    input_lines = f.readlines()

calibration_values = []

for line in input_lines:
    first_digit = None
    last_digit = None


    for i, char in enumerate(line):
        if char.isnumeric():
            first_digit = char
            break
    
    for j, char in enumerate(line[::-1]):
        if char.isnumeric():
            last_digit = char
            break

    calibration_values.append( int(first_digit + last_digit) )

print(sum(calibration_values))