2 digit module doesn't work

[SnJon]

Cool library! But I can't get this module to work correctly (work only first digit). It completely coincides with the schematic description for the library.
I am using the following code from the example:
`/*
ShiftDisplay example
by MiguelPynto
Print strings from Serial Monitor (250000 baud) on display
https://miguelpynto.github.io/ShiftDisplay/
*/

#include <ShiftDisplay.h>

const int LATCH_PIN = 6;
const int CLOCK_PIN = 7;
const int DATA_PIN = 5;
const DisplayType DISPLAY_TYPE = COMMON_ANODE; // COMMON_CATHODE or COMMON_ANODE
const int DISPLAY_SIZE = 2; // number of digits on display

ShiftDisplay display(LATCH_PIN, CLOCK_PIN, DATA_PIN, DISPLAY_TYPE, DISPLAY_SIZE);

void readSerial() {
char input[Serial.available() + 1]; // str len + NULL
int i = 0;
do {
char c = Serial.read();
if (c == '\n' || c == '\0')
break; // exit while
input[i++] = c;
} while (Serial.available() > 0);
input[i] = '\0'; // NULL terminate string
display.set(input); // save
}

void setup() {
Serial.begin(250000);
}

void loop() {
if (Serial.available() > 0)
readSerial();
display.update();
}`

What I'm doing wrong?