.input-group-prepend, .input-group-append {
    height: 32px;
}

.input-group > .form-control {
    flex: 1 1 !important;
}

.input-group>.form-control:not(:first-child) {
    border-top-left-radius: 0 !important;
    border-bottom-left-radius: 0 !important;
}
.input-group>.form-control:not(:last-child) {
    border-top-right-radius: 0 !important;
    border-bottom-right-radius: 0 !important;
}