#include <stdio.h>

int main() {
  FILE *fp = fopen("/proc/meminfo", "r");
  if (!fp)
    return 1;

  long long total = 0, available = 0;
  char line[256];
  while (fgets(line, sizeof(line), fp) && (!total || !available)) {
    sscanf(line, "MemTotal: %lld kB", &total);
    sscanf(line, "MemAvailable: %lld kB", &available);
  }
  fclose(fp);

  printf("Mem: %.0f%%\n", (double)(total - available) / total * 100);
  return 0;
}