Problem getting performance counters with Python

I’m trying to get the performance counters of a program (C application) running on the SiFive board with a Python script and then write it into a text file, but I get a lot of wrong data. The program running on the board is:

struct metal_cpu *cpu;
cpu = metal_cpu_get(metal_cpu_get_current_hartid());

if (metal_hpm_init(cpu) != 0) {
	return 1;

// a lot of stuff
// .
// .
// .

cnt = metal_hpm_read_counter(cpu, METAL_HPM_CYCLE);

printf("pc %d", cnt);

And I’m doing this on Python:

flag = 1
while flag:
    temp = ser.readline()
    temp_decode = temp.decode(encoding="UTF-8")

    if temp_decode == "\n":
        flag = 0

    f = open("results.txt", "a")

And when I run the program I get this on the results.txt:

How can I get the correct data? e.g. pc 43000 into the text file.